Characteristics And Evaluation Of Middle Ordovician Marine Carbonate Source Rocks In The Bohai Bay Basin

Based on the previous research and the analysis of the main core samples from the lower Paleozoic in the Bohai Bay basin, combining quantities of data, the paper has performed an integrated analysis of the types and content of maceral, abundance, types and maturity of organic matter and sediment organic phase in marine phase hydrocarbon source rocks of Ordovician carbonate sediments, revealed the special distribution character of the marine phase hydrocarbon source rocks of Ordovician carbonate sediments in Bohai Bay basin and delineated favorable hydrocarbon-generating blocks.The research approach to the study was organic petrology and organic geochemistry methods: Oil light, Fluorescence observations macerals and to their qualitative and quantitative; through rock pyrolysis come to the TOC, hydrocarbon potential (S1 + S2) and bituminous "A" taken for hydrocarbon source rocks abundance evaluation; Applying the method of restoring organic types means combining the method of the types of index hydrocarbon production index and the oil production index to resume working Ordovician types of organic matter. The study from the perspective of organic petrology reviewed Lower Paleozoic sector higher-mature source rock maturity indicators, applying the choice of lens-reflex rate asphalt reflectance, acritarch color index, rock pyrolysis parameters as the main analytical tools, identify research areas maturity characteristics. Evaluation based on favorable conditions blocks from hydrocarbon source rocks favorable hydrocarbon blocks for the establishment of the thickness of source rock, organic matter abundance, type, maturity, and organic type, burial history, the history of tectonic evolution of the research. The main source layer-generating potential: from a large number of data analysis it is not difficult to see the Ordovician three main hydrocarbon strata, lower-Majiagou group hydrocarbon potential is the smallest; Fengfeng Group is the Bohai Bay Basin Ordovician main hydrocarbon layer, its hydrocarbon potential is similar to the Upper-Majiagou group, but liquid hydrocarbon production scope is bigger than the latter and the thickness of source rock is less than the latter. According to these parameters right in front of the different strata and different regions of numerical analysis from the source rocks for hydrocarbon generation perspective, Bohai Bay Basin of the Lower Paleozoic sector carved out a favorable source areas: the southern Dagang (Nanpi - Kongdian), a favorable source; a favorable gas-generating areas: Shengli in the northeast (Zhanhua - Chezhen) favorable gas-generating area; two more favorable source areas: Shengli in the Western (Kanggu 4 - Qugu1 area) more favorable source, the northern China Central Plains (Guantao area) more favorable source; two more favorable gas-generating ares : the northern (Baxian - Langfang) a favorable gas-generating area, Southwest of North China (Jinxian County area) a gas-generating area.